Democratic strategists say there is little evidence that liberal groups including Progressive Change, MoveOn.org, and Democracy for America, founded by Howard Dean, have amassed the kind of power that Tea Party groups have within the Republican Party. But many nonetheless disagree with Progressive Change’s goals.

“This is an opening salvo to a change in the Democratic Party,” said Neil Sroka, communications director for Democracy for America. “There was a long time where it was thought that the future of the Democratic Party was somehow finding a terrain where you could be Republican-lite. What you’re seeing now is a moment where that whole facade is collapsing.”

REACTION FROM THE LEFT: DEMOCRACY FOR AMERICA IN A STATEMENT: “We will not accept a budget that forces average Americans to lose critical income over the holidays while leaving the wealthiest Americans untouched. Tell Congress to reject this proposal immediately.”

The Social Security spat last week is exemplary: In that fight, the Progressive Change Campaign Committee activated its huge membership against Third Way-affiliated Democrats and in defense of Warren. It was backed up by Howard Dean’s Democracy for America and Russ Feingold’s Progressives United. The collective push simultaneously cowed the corporate Democrats and prompted Warren herself to go on the offensive with a formal demand for groups like Third Way to better disclose their funders.

Let me just point out, though, that there's some split on the left as well. Democracy for America sent out an e-mail today that begs the Democrats not to pass this budget because it didn't go far enough to the left.

KUCINICH: But Democracy for America hasn't stirred thing up along the way, the way the conservative groups have for Republicans. And if the leadership -- I don't care where you are in leadership, someone had to speak out against these grips and someone had to take that stand, because they're going to keep going and keep picking off these members for things -- John Boehner takes you anything right with these groups. So I think there had to come a time where he had to push back forcefully and he chose this.

CUPP: Well, Congressmen Becerra, let me bring it back to the Democrats. Talking about the civil war in the GOP, but as I mentioned, Democrats are not completely aligned with this bill, either.

In fact, there seems to be a fissure. Democracy for America, a progressive organization, sent out an e-mail today to members, telling Democrats not to vote for this. They were like "Democrats can't continue to pretend they represent our interests and then accept legislation that hurts working families."

Several liberal advocacy groups, including the Campaign for America’s Future and Democracy for America, are lobbying Democrats to sink the proposal based on the exclusion of a UI extension.

“By failing to include an unemployment insurance extension in the budget deal, negotiators have declared ‘War on Christmas’ and potentially sentenced millions of struggling Americans to a very bleak New Year,” Jim Dean, head of Democracy for America, said in a statement. “Rather than caving in to Paul Ryan and other House Republican Ebenezer Scrooge impersonators, Democrats should stand strong and reject any budget deal that fails to adequately protect those who continue to look for work.”

Democrats, and particularly progressives, aren't thrilled with the final budget deal either, which helps explain their lack of elation over the Republican politics of it. The deal lacks an extension of long-term unemployment insurance, asks federal employees to pay in more to their pensions, and lacks other Democratic priorities. Left-leaning Democracy for America referred to it not as a compromise, but as "a sellout."